The best way to learn android app development

1)  https://kotlinlang.org/

2) https://www.codecademy.com/
3) https://blog.mindorks.com/
4) https://guides.codepath.com/android
4) https://guides.codepath.com/android
5) http://www.traininginannanagar.in/
6) https://developer.android.com/index.html
7) https://www.udacity.com/
8) https://code.tutsplus.com/categories/android
9) http://www.androidhive.info/
10) https://www.youtube.com/
11) https://www.youtube.com/
12) https://www.youtube.com/
13) https://www.quora.com/
14) https://stackoverflow.com/
15 ) https://android-developers.googleblog.com/ 
16) Android-Design-Cheat-Sheet-highres